They already have it, Toad. Easy to produce, charming, and not a 2D platformer. Make one for every EoY holiday or something, and let it sell then. It gives them much needed variety, for one, and it tackles a genre they haven't really touched in some time: puzzles (outside of Pushmo... which is a successful franchise). Heck, make a Pushmo X Captain Toad
. These types of projects also work mostly of pre-made assets, so it doesn't require large teams.
Family friend in the middle of summer seems irrelevant to me. And its not that Yoshi is or isn't a "super strong brand", its not even a average brand to begin with. Its always been an under-performer relatively speaking. So while it may be a good game, its a good game with baggage and goes into that long, long post that Nirolak had about brand growth and consumer confidence in your product.